The overall goal of this amended application is to examine the role of prenatal factors, particularly diet (specifically, trans fatty acids, n-3 fatty acids and calcium), in outcomes of pregnancy and infancy. A total of 6,000 women will be enrolled during their first 12 weeks of pregnancy into the Harvard Pilgrim Health Care Cohort and will be followed along with their offspring until six months postpartum. The influence of specific nutrients on pregnancy outcomes, including fetal growth, length of gestation, and incidence of pre-eclampsia will be assessed. In addition, the effects of these same exposures on infant development and cardiovascular risk factors during the first six months of life will be examined. Four hypotheses will be tested: 1) maternal intake of trans fatty acids is inversely associated with fetal growth, length of gestation, and infant cognitive development; 2) maternal intake of n-3 fatty acids is directly associated with fetal growth, length of gestation and infant cognitive development; 3) maternal intake of calcium is inversely associated with incidence of pre-eclampsia and blood pressure levels in infancy; and 4) maternal intake and red blood cell level of n-3 fatty acids are inversely associated with incidence of pre-eclampsia. Blood samples and detailed data on gestational diet at several times during pregnancy will be collected along with sociodemographic variables, health habits, medical and family history, reproductive history and psychosocial conditions. Fetal growth data will be assessed from ultrasound examinations. Birth weight, height and other anthropometric data and blood pressure will be obtained and the offspring will be followed for 6 months to assess growth, cognitive development and blood pressure. There are plans to provide new avenues for the prevention of common adverse conditions of pregnancy, childhood and, perhaps, adulthood with the prospective, longitudinal study.